Citazione Stile APA (7a Edizione)

Engelken, R., Engelken, R., & Slattery, P. (1981). The art of natural farming & gardening. Barrington Hall Press.

Citazione stile Chigago Style (17a edizione)

Engelken, Ralph, Rita Engelken, e Pat Slattery. The Art of Natural Farming & Gardening. Greeley, Iowa: Barrington Hall Press, 1981.

Citatione MLA (8a ed.)

Engelken, Ralph, et al. The Art of Natural Farming & Gardening. Barrington Hall Press, 1981.